1. Field of Invention
This invention refers to double handle knives and blades and handle attachments to convert a knife or single handle blade into a double handle blade, and specifically to improvements in the positioning of the secondary handle that allow for greater ease and accuracy in the cutting of food items and other objects.
2. Background of Invention
The vast majority of kitchen knives in use today employ conventional handles extending off the back end of a blade whereas the front of the blade comes to a point. These knives allow a user to grip the knife with their dominant hand leaving their non-dominant hand free to control the food item or other object being cut. This arrangement allows precise cutting of the item but has the disadvantage that the dominant hand is doing most of the work. This often leads to hand and wrist fatigue especially for the elderly, people predisposed to wrist injury, and others who prepare a lot of difficult to cut foods such as carrots, squash, pumpkins, potatoes, frozen foods, and so forth. To help alleviate this, people sometimes use their non-dominant hand to assist their dominant hand in cutting through a food or other item. This may be done by positioning the food item with the palm and thumb of the non-dominant hand while simultaneously using the index and middle fingers of the same to press down on the top front of a blade, gripping the handle with the dominant hand and raising it to clear the food item, then levering down cutting through it with the assistance of the non-dominant hand. However, pressing down on the top of the thin blade with the fingers can be very uncomfortable and limits the downward force that is possible.
Double handle knives, in addition to a primary handle used by the dominant hand, provide a secondary handle for use by the non-dominant hand so that both hands can comfortably apply downward pressure on broad handles. Using the four available fingers (thumb excluded) of the non-dominant hand to press down evenly on the secondary handle would provide maximum benefit and minimize hand and wrist fatigue. However none of the prior art double handle knives provide secondary handles designed for the dual purpose of allowing the palm and thumb of the non-dominant hand to remain close to the blade to control short pieces of food while also leaving the remaining four fingers of the same hand in a position to press down evenly on the secondary handle. This includes those that require both hands to wrap around the handles as disclosed in patents: A. Haas U.S. Pat. No. 986,166 and Li Xiaoping Chinese Pat. No. CN2247586Y with vertical handle grips; Watermolen and Peters U.S. Pat. No. 5,920,992 with rising handles with finger grips; Wang Xiaobo Japanese Pat. No. JP11300058 and John Erikson U.S. Pat. No. 1,706,918 with a secondary handle built on the back top of a knife blade; W. L. Iwan U.S. Pat. No. 696,050 with handles at right angles at the back of the blade.
Dexter-Russell (Product no. 09210) makes a double handle “cheese knife” with a conventional design handle on each end as well as a handle attachment (product no. 18000) for adding an additional handle to pizza knives. This attachment may conceivably be used to attach to a kitchen knife as well. Additionally, Carl Carrillo U.S. Pat. No. 6,493,946 made a knife guard that can be applied to the top of a blade and used as a secondary handle. With these designs, the long axis of the secondary handle is parallel to the blade. However, a parallel arrangement (see FIG. 2C) is not ideally suited for the dual purpose of pinning down the front of the knife and assisting in the cut while also positioning the food item for the cut as there is a tendency for the index finger to exert significantly greater downward pressure than the other fingers and for other reasons as discussed in the primary operation of the main embodiment.
Barker and Barbour U.S. Pat. No. 230,393 developed a handle attachment that adds an additional handle to knives intended for cutting cheese. The handle design is very high profile and not suited for both assisting in the cutting and controlling of food items by the non-dominant hand. Furthermore, the long axis of the handle is perpendicular to the blade. A perpendicular arrangement (see FIG. 2D) is not ideally suited for the dual purpose of assisting in the cut while also controlling the food item as the fingers are unevenly placed on the handle creating unnecessary side torque as downward pressure is applied. The dominant hand would have to counteract this torque to keep the blade straight thus creating more stress on the wrists.
J. P. Smith U.S. Pat. No. 331,915 developed a knife having a conventional handle on one end and a high profile round handle extending off the top of a blade. The high profile handle makes it convenient for cutting high blocks of cheese but more difficult for the dual purpose of both cutting and controlling food items with the non-dominant hand. Furthermore, a round handle doesn't provide an ideal arrangement for the dual purpose of both positioning the food item and levering maximum downward pressure to cut it: because if a round handle was large enough to accommodate all four fingers of the non-dominant hand, over 3″ diameter, the fingers would be mostly contacting the handle on one side of the blade thereby creating side torque as downward pressure is applied (see FIG. 2E).
Yet another limitation of the prior art is when the non-dominant hand is not required for controlling the food item or other object: now that the non-dominant hand and arm are free to assume a variety of positions to find the one most effective for the given situation, they are limited by the fixed position of the secondary handle itself. This is especially true with harder to cut items.